1. Technical Field
The disclosure relates to a peptide, and more particularly to a peptide for transmigration across the blood brain barrier and a delivery system comprising the same.
2. Description of the Related Art
The blood brain barrier (BBB) is composed of brain endothelial cells capable of blocking foreign substances, such as toxins, to enter therethrough, due to tight junctions therebetween. However, hydrophobic or low-molecular-weight molecules can pass through the BBB via passive diffusion.
Some active compounds, for example, hydrophilic protein drugs for treating cerebral or nervous diseases, cannot enter brain tissue via passive diffusion due to their large molecular weight or hydrophilicity.
Accordingly, structural modification of drugs has been developed to increase hydrophobicity of drugs, allowing various active compounds to pass though the BBB. Other methods for allowing hydrophilic or macromolecular drugs to pass through the BBB includes, for example, absorption-mediated transport (AMT) allowing positive-charged carriers to pass through the BBB via charge absorption, carrier-mediated transcytosis (CMT) allowing hydrophilic metal ions such as Na+ and K+, di-peptides, tri-peptides or glucose to pass through the BBB via transporters, and receptor-mediated transcytosis (RMT) allowing macromolecules such as insulin, transferrin, or low-density lipoprotein (LDL) to pass through the BBB via transcytosis.